1. Field of the Invention
The present invention relates to a collaborative robot for performing an operation while sharing a work space.
2. Description of the Related Art
In industrial robots, in order to enhance the safety of a person, a safety fence is provided around the movable area of a robot, to restrict entry of the person to the movable area of the robot. However, in recent years, an industrial robot, in which some measure is used, in place of the safety fence, to sufficiently enhance the safety of a person, can perform an operation while sharing a work space with the person. This increases the demand for such a robot, so-called collaborative robot.
The use of a collaborative robot system enables a person and a robot to perform different operations within the same space, or enables a person to perform an operation for a workpiece gripped by a robot. However, when a collaborative robot is used, a person and a robot share a work space, and accordingly, it is necessary to prevent the person from colliding with the robot and being injured.
Especially, there is a high possibility that an operator performs an operation near a working tool attached to the wrist of a robot, and accordingly, it is necessary to prevent the operator from being injured even when the working tool collides with the operator.
For example, Japanese Patent No. 5835276 (hereinafter referred to as Patent Document 1), Japanese Unexamined Patent Publication (Kokai) No. 2014-76524 (hereinafter referred to as Patent Document 2), and Japanese Patent No. 5902664 (hereinafter referred to as Patent Document 3) disclose a structure for covering a part of a robot.
Patent Document 1 proposes a structure in which a robot hand is covered by a bag-like member. This proposal is to cause the robot hand to have cleaning performance and dust-proof and drip-proof performance for antibacterial protection, to utilize a robot in biomedical field.
Patent Document 2 proposes a robot in which fingers of a robot hand capable of gripping an object are covered by an elastically deformable member, to reliably grip the object.
Patent Document 3 proposes a collaborative robot in which a robot arm is covered by a protective member.
However, Patent Document 1, Patent Document 2, and Patent Document 3 do not disclose a technology intended to reduce a dangerous risk, which may occur when a working tool attached to a wrist of a robot collides with a person. In other words, a proposal to implement a countermeasure for the working tool itself, which reduces a dangerous risk at the time of collision between the working tool of the robot and the person, has not been conventionally made.
The bag-like member covering the robot hand disclosed in Patent Document 1 is not a member for absorbing a shock of collision with a person, and is a member for maintaining sanitation. The elastically deformable member for covering fingers of the robot hand disclosed in Patent Document 2 is a member for reliably gripping an object, but is not a member for absorbing a shock of collision with a person. Further, in the collaborative robot disclosed in Patent Document 3, the robot arm is merely covered by the protective member.
As described above, in the collaborative robot, there is a high possibility that the operator robot performs an operation near the working tool attached to the wrist of the robot. As the use of the collaborative robot expands, the importance of making a countermeasure for preventing collision in the working tool itself increases hereafter, in order to enhance the human safety. Further, the working tool attached to the frontmost end of the robot arm moves at a speed higher than the arm of the robot main body, and accordingly, probably become the greatest risk source when the robot moves.